This invention relates to hoses wherein water from the interior of the hose weeps through the hose wall to wet a textile exterior surface of the hose, thereby protecting the hose from damage when contacted by embers or flames.
Many hoses for fighting forest fires have been made of unlined linen which becomes wet in the course of ordinary use to resist damage from embers and flames. Such hoses have a textured interior wall which produces substantial hydraulic friction losses and pressure drops, creating difficulties in delivering sufficient pressures and quantities of water to the nozzle. While in use, the rate of water leakage decreases progressively to reduce the fire resistance of the hose. After the fire is extinguished, such hoses become somewhat rigid due to swelling of the linen, making it difficult to get the hoses from the fire site to a location where they can be dried for storage. Unless properly dried and stored, such hoses are also susceptible to mildew damage.
There also have been woven water-pervious hoses interiorly coated or lined with a minutely porous plastic film. Fabrication of such hoses is extremely difficult and requires special machinery. Further, minerals or water pollutants in some areas block the minute pores in the lining, leaving the textile hose covering dry and subject to fire damage.
The present invention relates to a weeping hose which has an external exposed tubular jacket formed of water absorbent textile material, an internal elastomer tube formed of water impermeable material which lines the textile jacket, and water-releasing openings in the elastomer tube, such openings being formed of spaced apart sets of radiating cracks in the elastomer lining. The edges of the cracks are normally in contact with each other but are separable to permit water to pass from the interior of the hose into the jacket when the tube is subjected to internal hydrostatic pressure. The sets of cracks are appropriately spaced to produce wetting of substantially all of the external jacket when the interior of the hose is subjected to normal firefighting hydrostatic pressures.
The hose forming method involves the driving of a needle through spaced apart locations on a tubular body formed of an internal elastomer tube covered by an external exposed jacket of water absorbent textile material. Penetration of the needle forms a plurality of spaced apart sets of radiating cracks in the tube which enable water under hydrostatic pressure to pass from the interior of the tube into the jacket where it is absorbed to protect the jacket from fire damage.